(Arboricultural-styled) 'Fact of the Day'

[tree-fancier123]

If gene expression is said to be 'regulated' by various ions and biomolecules, then upregulated must mean a temporary increase in gene transcription and translation, in this case "of at least 2.5% of the entire genome" in arabidopsis etc.

So this movement induced influx of calcium may be tied in with how 'reaction wood' is formed. Funny how they know the knitty gritty of everything these days, in the old days it must have been like - yeah it's a tree, made of wood that is

[Kveldssanger]

It is fascinating indeed, though from reading this book it is clear there is much more to be understood. For example, how exactly plants 'perceive' temperature, moisture, etc, is not well-researched. There is no understanding of how plants 'perceive' cold, for example - we know how plants respond to cold, but have no idea how they actually recognise that it is cold, and getting colder or warmer. It's complex, indeed. Plants can even 'remember' how to 'deal' with the cold - 'naive' plants suffer more than 'hardened' plants to cold, for example.

 

One interesting thing this book mentions is that plants can 'remember' they have been through a period of vernalisation (a very cold period) for up to 300 days, assuming the light conditions are wrong for those 299 days before light suddenly becomes 'good enough' for flowering on the 300th day (as cold alone doesn't facilitate flowering - a series of 'conditions' must be met, of which a cold period is just one). After that, they seem to 'forget'. I am sure it is different for each species, however. To add to this point, we also do not know how plants 'know' how long a cold period has gone on for.

 

There is such a long way to go with research that I feel we're just wandering at the threshold of true knowledge.

Edited September 25, 2015 by Kveldssanger

[Kveldssanger]

25/09/15. Fact #42.

 

Bit of a different one, but from the same book.

 

Building from the above post of mine on vernalisation, we currently understand that vernalisation does not (at least directly) transfer from parent to seed. For example, if the parent goes through a particular set of environmental conditions, the seed is not pre-natally determined to vernalise in a different manner by default.

 

Now for some context...

 

The term itself was coined by Russian geneticist Trofim Lysenko in the early 20th century. During his research on vernalisation, he fabricated his results in an attempt to prove that vernalisation under favourable conditions would permanently improve genetic stock. Alarmingly (though this no doubt still goes on today within the industry, though to different extremes in different subjects), critics who suggested he was wrong with his results (not knowing they were fabricated) were coerced into silence or shipped off to Siberian labour camps. This crippled the Soviet plant biology 'movement' for a long while, and lead to Western scientists categorically (but incorrectly) dismissing that vernalisation can impact upon offspring - offspring phenotype is influenced by the genes it inherits from its parent(s), and by parental experiences.

Source: Karban, R. (2015) Plant Sensing & Communication. USA: The University of Chicago Press.

Edited September 25, 2015 by Kveldssanger

[armybloke]

To add to the above point, the book continues to suggest that recent advances have identified jasmonic acid being implicated in the overall process to touch response. Interestingly, where certain plants studied were unable to 'produce' jasmonic acid, mechanostimulant responses were non-existent.

 

There really is so much to this Plant Sensing & Communication book. It is truly fascinating. Get it if you can! It's good value, for such a comprehensive book.

 

Yep you talked me in to buying the book, sounds like a must read. Thanks for the tip!

[Kveldssanger]

Good stuff!

 

I'm on p46 of 197 right now. It's a tough read in some respects, though very fruitful. So much new information packed into the pages. Most reference are from the turn of the milennia, and many are even from the 2010-2015 period. It really does deal with cutting-edge stuff. Will be interested to see if a second edition comes out in the future, with updates text.

Edited September 25, 2015 by Kveldssanger

[daltontrees]

I do understand where you are coming from. If I am honest, the author of the book has a good way of explaining things. Only a few things thus far have gone 'over my head', so to speak.

 

If I were to paraphrase this:

 

"This localised influx in calcium ions upregulates genes in the 10-30 minute following stimulation, inducing adaptive growth. Particular species, such as Arabidopsis spp., may see at least 2.5% of the entire genome being 'upregulated' following such stimulation. In many other species, it is however likely to be less."

 

I would say:

 

Cellular increases in calcium ions local to the stimulated area induce (through a far more complex series of events) a heightened sensitivity and thereby initiate adaptive growth responses (through the creation and distribution of hormones such as auxin), in the 10-30 minutes following on from initial stimulation.

 

Yes, I am paraphrasing my own parahrase!

 

Cheers, I see the flaw now to be more the width of the term 'adaptive growth' than the meaning of upregulation.

[Kveldssanger]

26/09/15. Fact #43.

I could share so many facts from this book that I could do one each day for a year and still not cover all the awesome things found within.

 

A tree is naturally compartmented, from the intra-cellular level through to the cellular level, and from the cellular level through to the 'macro' level (rays and rings segment the structure into many small sections). This makes it difficult for a pathogen to invade, by a sort of default.

 

However, things can spice up a bit when one considers that there is phenotypic variation within a single specimen in response to different localised environmental conditions. To illustrate, consider two roots branching from the same 'parent' root. One is growing into an area of higher phosphates, whilst the other isn't. Because of the localised heterogeneity of the soil environment, the roots will grow in different manners (one may be longer, 'healthier', thicker, etc, than the other).

 

This phenotypic variation has been shown to make it more difficult for pathogens to exploit the host, both ecologically and evolutionarily (i.e. it's harder right now for the pathogen to invade, and it will be just as hard for following generations). One may even consider, as the localised environments around a tree change, that 'targets' within the tree (weak spots) shift. This makes it even more difficult for invasion from pathogens.

 

Now obviously pathogens have their own strategies to counteract this, though considering this concept makes the plant-pathogen relationship yet more intriguing.

 

Sources:

 

Adler, F. & Karban, R. (1994) Defended fortresses or moving targets? Another model of inducible defenses inspired by military metaphors. American Naturalist. p813-832.

 

Karban, R. (2015) Plant Sensing & Communication. USA: The University of Chicago Press.

 

Karban, R., Agrawal, A., & Mangel, M. (1997) The benefits of induced defenses against herbivores. Ecology. 78 (5). p1351-1355

Edited September 26, 2015 by Kveldssanger

[Kveldssanger]

Cheers, I see the flaw now to be more the width of the term 'adaptive growth' than the meaning of upregulation.

 

Language is a flawed medium.

[Kveldssanger]

Non-random thoughts - with plants being so complex in terms of what they respond to from cues and signals, the internal cues and signals that operate within, and the cues and signals they give out to other plants, predators, parasites of predators, etc, I do wonder what governs it all. This book suggests there may be a sort of Central Nervous System for the plant, given the sheer complexity of it all. I am yet to find out whether the author delves into this more - I do hope so.

 

Plants even 'remember' that they have 'received' certain cues and signals for minutes, days, or even months, so this adds another level onto the above situation.

[tree-fancier123]

This book suggests there may be a sort of Central Nervous System for the plant

 

according to current thinking all life started in the sea as a prebiotic soup, then plants then animals much later, so why not a plant nervous system evolved in a similar way to that in animals?. Maybe somewhere in the universe there are plants with brains, like humans who don't need the supermarket.

Even a single bacterium is so complex - a machine that can make copies

 

From Scientific American -

"A big mistake people make is speaking as if plants 'know' what they're doing," says Elizabeth Van Volkenburgh, a botanist at the University of Washington. "Biology teachers, researchers, students and lay people all make the same mistake. I'd much rather say a plant senses and responds, rather than the plant 'knows.' Using words like 'intelligence' or 'think' for plants is just wrong. Sometimes it's fun to do, it's a little provocative. But it's just wrong. It's easy to make the mistake of taking a word from another field and applying it to a plant."

Plants cannot "think and remember," but there's nothing stupid about them: They're shockingly sophisticated - Observations - Scientific American Blog Network